An azomethine dye, particularly an azomethine dye in which p-dialkylaminophenyl group is conneced to a nitrogen atom in imine is produced by the oxidative coupling reaction of an active methylene or phenol with an N,N-dialkyl-p-phenylenediamine. Such an azomethine dye has a wide range of tones such as yellow, red, magenta, blue and cyan and thus has been widely used as an image forming dye for silver halide color photographic materials for use in the subtractive color process with three colors, i.e., yellow, magenta and cyan. Blue and cyan dyes are produced from phenols, naphthols and 2,4-diphenylimidazoles. Magenta and blue dyes are produced from 5-pyrazolones, acylacetonitriles, 1H-pyrazolo[1,5-a]benzimidazoles, 1H-pyrazolo[5,1-c]-1,2,4-triazoles, and 1H-pyrazolo[2,3-b]-1,2,4-triazoles. Yellow dyes are produced from acylacetanilides, diacylmethanes and malondianilides. These dyes are further described in JP-A-60-186567, JP-A-63-145281 and JP-A-63-113077 (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
In recent years, new color image forming methods such as color electrophotography, ink jet process and heat-sensitive transfer process have been proposed. On the other hand, the increasing demand for filters for solid image pickup tube and color liquid crystal television coupled with the development of electronic imaging has caused azomethine dyes to be applied and studied not only in color photography but also in various systems or merchandises. Further, dyes which exhibit absorption in the infrared region are disclosed in JP-A-3-81192, JP-A-3-81193, JP-A-3-81194, and JP-A-2-172794.
However, these azomethine dyes have many disadvantages. For example, they exhibit a low fastness to heat, moisture, light, chemicals, air, etc., can hardly be synthesized and are expensive.
In particular, many of azomethine dyes which exhibit absorption in the near infrared region have a low fastness. Thus, the development of azomethine dyes having a high fastness have been keenly desired.
Moreover, these known azomethine dyes show a broad absorption wavelength or exhibit unnecessary absorption. Thus, they leave much to be desired as image forming dyes or filter dyes,
Besides the above mentioned disadvantages, these known azomethine dyes have further disadvantages that when used as heat transfer dyes, they can hardely heat-migrate, they exhibit a low fastness to heat, light, moisture, air, oxygen, chemicals, etc., they are susceptible to a drop in the image sharpness, they can easily be retransferred, they can hardly form a heat transfer dye providing material (that is, they have a low solubility), they are susceptible to image bleeding with time, and they can deteriorate the light fastness of other dyes.